1. Field of the Invention
The present invention relates to a linear actuator and a method for controlling the same, and more particularly, to a linear actuator converting a rotational force of a motor into a linear movement and a method for controlling the same.
2. Discussion of Related Art
A motor is provided with a shaft which is rotatably formed, a rotor coupled to the shaft, and a stator secured inside a housing, and the stator is installed along a periphery of the rotor with a space therebetween. In addition, a coil is wound around the stator to form a rotating magnetic field so that an electrical interaction between the coil and the rotor is caused to induce rotation of the rotor.
Power output from the motor as described above is a rotational force. Therefore, in order to utilize the rotational force of the motor as power by which a component is moved linearly, a separate power converting means is required. The example of such a power converting means can be an actuator including a motor in which a lead screw is mounted.
Recently, a variable type head lamp which can maximally secure a driver's visual field at night in response to a steering direction of the driver has been proposed, and the motor in which the lead screw is mounted may be employed as the actuator which realizes swiveling and leveling of the head lamp.
In general, the motor realizing the linear driving as above can be referred to as a step motor, and a nut to be connected to a component may be mounted on a lead screw of the step motor.
In the step motor mentioned above, if a restriction occurs in connection relations between components or a control pulse is not output, the components are not located at their target positions, and it is difficult for a user to verify the above fault due to a characteristic that the step motor is controlled via the uni-directional pulse.